Measurement method for thickness and flow of gas-liquid two-phase annular flow liquid film in vertical pipe

A measurement method and technology of liquid film thickness, which is applied in the direction of measuring fluid flow by measuring pressure difference, volume/mass flow generated by mechanical effects, etc., can solve problems such as measurement deviation and turbulence, and achieve simple operation, low cost, and detection high precision effect

CN107270980AActive Publication Date: 2017-10-20XI AN JIAOTONG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2017-10-20

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Abstract

The invention discloses a measurement method for the thickness and the flow of a gas-liquid two-phase annular flow liquid film in a vertical pipe. The method includes the following steps that (1) the pressure drop gradient dP / dz of the gas-liquid two-phase annular flow in the vertical pipe is measured, the shear stress tau<w> between a liquid film of the gas-liquid two-phase annular flow and the wall in the vertical pipe is measured; (2) a columnar control volume is selected for force analysis on a gas core, a gas core momentum equation is obtained, and an annular control volume is selected for force analysis on the liquid film to obtain a liquid film momentum equation; (3) according to the gas core momentum equation and the liquid film momentum equation, the shear stress tau in the liquid film is obtained; (4) according to the pressure drop gradient dP / dz of the gas-liquid two-phase annular flow in the vertical pipe, the shear stress tau<w> between a liquid film of the gas-liquid two-phase annular flow and the wall in the vertical pipe and the shear stress tau in the liquid film, the radius r of the gas core of the gas-liquid two-phase annular flow in the vertical pipe is calculated, and then the thickness and the flow of the gas-liquid two-phase annular flow liquid film in the vertical pipe are calculated according to the radius r of the gas core of the gas-liquid two-phase annular flow in the vertical pipe. According to the method, detection of the thickness and the flow of the gas-liquid two-phase annular flow liquid film in the vertical pipe can be achieved, the method has high detection precision, safety and reliability, and the detection cost is low.
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Description

technical field

[0001] The invention belongs to the technical field of gas-liquid two-phase annular flow parameter measurement, and in particular relates to a method for measuring the liquid film thickness and flow rate of gas-liquid two-phase annular flow in a vertical pipe. Background technique

[0002] Gas-liquid two-phase annular flow is a common two-phase flow form in petroleum, chemical and other industrial fields. The annular flow in a pipe is usually composed of a gas nucleus entrained with small liquid droplets and a liquid film attached to the wall. Accurate non-invasive measurement of liquid film thickness and flow rate is of great significance for in-depth understanding of the flow characteristics of annular flow. According to different measurement principles, the existing liquid film detection technology can be divided into ultrasonic method, optical method, ray method and conductometric method. The ultrasonic method is based on the principle of attenuation and...

Examples

Embodiment Construction

[0047] The present invention is described in further detail below in conjunction with accompanying drawing:

[0048] refer to figure 2 and image 3 , the measuring method of gas-liquid two-phase annular flow liquid film thickness and flow rate in the vertical pipe of the present invention comprises the following steps:

[0049] 1) Measure the pressure drop gradient of the gas-liquid two-phase annular flow in the vertical pipe through the differential pressure transmitter 2 Then measure the shear stress τ between the gas-liquid two-phase annular flow liquid film and the pipe wall in the vertical pipe through the shear stress sensor 1 w ;

[0050] 2) Select the columnar control body to analyze the force of the gas core to obtain the momentum equation of the gas core, and select the annular control body to analyze the force of the liquid film to obtain the momentum equation of the liquid film;

[0051] 3) According to the gas core momentum equation and the liquid film momen...